The present invention relates to an optical disc reproducing apparatus, and particularly to a circuit for controlling the position of a pickup to reproduce information recorded on both sides of a disc.
Generally, most common optical disc reproducing apparatuses reproduce audio information recorded on one side of a disc. On the other hand, when video information is recorded together with audio information, the amount of recorded information doubles. Therefore, optical disc reproducing apparatuses are used in which information is recorded on both sides.
FIG. 1 shows sectional views of an example of a conventional pickup transfer for an optical disc reproducing apparatus, which centers around a disc 80 having information on both sides. It is assumed that the first reproducing side (side A) of the disc faces downward in FIG. 1A, and upward in FIG. 1B. Here, upward means that while seating disc 80, the user can see the side of the disc, and downward means the disc's side is unable to be seen and faces a spindle motor 50. With disc 80 situated as illustrated in FIG. 1A, the reproducing operation is performed as follows.
First, a reproducing command is applied to spindle motor 50 in order to rotate disc 80. Then, when the revolution speed becomes normal (e.g., 1800 rpm), a pickup 60 picks up the information recorded on disc 80. At this time, the movement of pickup 60 along a pickup transfer 1 is controlled by a feed motor 70. In other words, the transferring movement is controlled from the innermost circumference to the outermost circumference, and from the upward side to downward side and vice versa. When the outermost information on side A is picked up by such pickup movement control, feed motor 70 transfers pickup 60 along pickup transfer 1 to the innermost circumference of the second reproducing side (side B). After the transferring movement is completed, spindle motor 50 is reversely rotated while performing the identical operation to the reproducing of side A.
In FIG. 1B as in FIG. 1A, respective operations of spindle motor 50, pickup 60, and feed motor 70 are each controlled to reproduce from the innermost circumference of downward side. However, since the downward side is detected as the second reproducing side by read-in information included on the downward side, pickup 60 is transferred to the innermost circumference of the upward side along pickup transfer 1. Then, reproduction is performed from the innermost circumference to the outermost circumference of disc 80 while reversely rotating spindle motor 50. When the information on the outermost circumference of the upward side is picked up, pickup 60 is transferred to the innermost circumference of the downward side, and reversing the rotation of spindle motor 50. Thereafter, the reproducing operation proceeds. If the STOP key is pressed or reproduction is completed during the control of the reproducing operation, feed motor 70 is controlled to move pickup 60 to the position on the downward side's innermost circumference of disc 80.
However, if the power is turned off, pickup 60 stays at the position it was just before the reproducing operation ceased. Therefore, upon power-up, feed motor 70 requires sufficient drive current for the transfer of pickup 60. Moreover, with disc 80 seated as illustrated in FIG. 1B, pickup 60 must be transferred from the starting point of the reproducing operation while controlling the rotation direction of spindle motor 50. This retards the reproducing time and increases power consumption.